JP2017040606A - Sensor device and electric power steering device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor device capable of suppressing variation according to switching to calculation using a normal signal, in the case where abnormality occurs in one part of the signal, and to provide an electric power steering device using the same.SOLUTION: A sensor 1 includes: a main sensor part 10; a sub sensor part 20; and an ECU 40. A torque calculation part 43 of the ECU 40 regards a main steering torque Tm calculated based on a main sensor signal as a steering torque Tq, in the case where a main output signal Sm is normal. Also, the torque calculation part 43 calculates the steering torque Tq on the basis of a sub steering torque Ts calculated based on a sub sensor signal and the main steering torque Tm before abnormality is detected, in an unconfirmed period from the detection of the abnormality in the main output signal Sm until the abnormality is confirmed. Thereby, when abnormality occurs in one part of the signal, variation in the steering torque Tq according to switching to the calculation using a normal signal can be suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sensor device and an electric power steering device using the sensor device.

  Conventionally, sensor devices that transmit sensor data to a controller are known. For example, in Patent Document 1, the transmission of sensor data is synchronized by a trigger signal generated by a controller and received by a bidirectional node.

Special table 2013-546096 gazette

By the way, sensor data may become abnormal due to abnormality of the sensor element. However, Patent Document 1 does not mention anything about how to handle sensor data when an abnormality is detected.
The present invention has been made in view of the above-described problems, and its object is to suppress fluctuations associated with switching to computation using a normal signal when an abnormality occurs in some signals. A sensor device and an electric power steering device using the sensor device are provided.

The sensor device of the present invention includes a main sensor unit (10), a sub sensor unit (20), and a control unit (40, 50).
The main sensor unit includes main sensor elements (11, 12) and a main output circuit (15). The main sensor element detects the target physical quantity. The main output circuit generates and outputs a main output signal including a main sensor signal corresponding to the detection value of the main sensor element.
The sub sensor unit includes sub sensor elements (21, 22) and a sub output circuit (25). The sub sensor element detects a target physical quantity. The sub output circuit generates a sub output signal including a sub sensor signal corresponding to the detection value of the sub sensor element, and outputs the sub output signal at a timing shifted from the main output signal for a predetermined period shorter than the length of one signal period. .

  The control unit includes a signal acquisition unit (41), an abnormality detection unit (42), and a physical quantity calculation unit (43). The signal acquisition unit acquires a main output signal and a sub output signal. The abnormality detection unit detects an abnormality in the main output signal and the sub output signal. The physical quantity calculation unit calculates a target physical quantity using at least one of the main sensor signal and the sub sensor signal.

  When the main output signal is normal, the physical quantity calculation unit sets the main physical quantity calculated based on the main sensor signal as the target physical quantity. Further, the physical quantity calculation unit detects a sub physical quantity calculated based on the sub sensor signal and an abnormality in an undetermined period that is a period from when the abnormality of the main output signal is detected to when the abnormality is confirmed. The target physical quantity is calculated based on the previous main physical quantity.

  The sensor device of the present invention includes a main sensor unit and a sub sensor unit, and the signal acquisition unit can acquire the main output signal and the sub output signal. Therefore, even if some of the signals are abnormal, the calculation of the target physical quantity is performed. Can continue. Further, the target physical quantity in the undetermined period is calculated based on the sub physical quantity and the main physical quantity before abnormality detection. Thereby, when abnormality arises in a part of the signals, it is possible to suppress fluctuations in the target physical quantity that accompany the switching to the calculation using the normal signals.

1 is a schematic configuration diagram illustrating a steering system according to a first embodiment of the present invention. It is a block diagram which shows the sensor apparatus by 1st Embodiment of this invention. It is a time chart explaining the communication frame of the main output signal by 1st Embodiment of this invention. It is a time chart explaining the output timing of the main output signal and sub output signal by 1st Embodiment of this invention. It is a flowchart explaining the torque calculation process by 1st Embodiment of this invention. It is a flowchart explaining the torque calculation process by 2nd Embodiment of this invention. It is a flowchart explaining the torque calculation process by 3rd Embodiment of this invention. It is a flowchart explaining the torque calculation process by 4th Embodiment of this invention. It is a flowchart explaining the torque calculation process by 5th Embodiment of this invention. It is a block diagram which shows the sensor apparatus by 6th Embodiment of this invention.

Hereinafter, a sensor device and an electric power steering device according to the present invention will be described with reference to the drawings. Hereinafter, in a plurality of embodiments, the same numerals are given to the substantially same composition, and explanation is omitted.
(First embodiment)
A first embodiment of the present invention is shown in FIGS.
As shown in FIG. 1, the sensor device 1 includes a sensor unit 5, an ECU 40 as a control unit, and the like, and is applied to, for example, an electric power steering device 80 for assisting a steering operation of a vehicle.

An overall configuration of a steering system 90 including an electric power steering device 80 is shown in FIG.
A steering wheel 91 as a steering member is connected to a steering shaft 92. The steering shaft 92 has an input shaft 921 as a first shaft and an output shaft 922 as a second shaft. The input shaft 921 is connected to the steering wheel 91. A torque sensor 83 that detects torque applied to the steering shaft 92 is provided between the input shaft 921 and the output shaft 922. A pinion gear 96 is provided at the tip of the output shaft 922 opposite to the input shaft 921. The pinion gear 96 is engaged with the rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

  When the driver rotates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into a linear motion of the rack shaft 97 by the pinion gear 96, and the pair of wheels 98 are steered at an angle corresponding to the amount of displacement of the rack shaft 97.

  The electric power steering device 80 includes a motor 81 that outputs auxiliary torque that assists the driver in steering the steering wheel 91, a reduction gear 82 as a power transmission unit, a torque sensor 83, an ECU 40, and the like. In FIG. 1, the motor 81 and the ECU 40 are separate, but may be integrated.

The reduction gear 82 reduces the rotation of the motor 81 and transmits it to the steering shaft 92. That is, the electric power steering apparatus 80 of the present embodiment is a so-called “column assist type”, but may be a so-called “rack assist type” that transmits the rotation of the motor 81 to the rack shaft 97. In other words, in this embodiment, the steering shaft 92 corresponds to the “driving object”, but the rack shaft 97 may be the “driving object”.
Details of the ECU 40 will be described later.

  The torque sensor 83 is provided on the steering shaft 92 and detects steering torque based on the twist angle between the input shaft 921 and the output shaft 922. The torque sensor 83 includes a torsion bar (not shown), a magnetism collecting unit 831 as a detection target, the sensor unit 5 and the like. The torsion bar connects the input shaft 921 and the output shaft 922 coaxially on the rotation shaft, and converts the torque applied to the steering shaft 92 into a torsional displacement. The magnetic flux collector 831 includes a multipolar magnet, a magnetic yoke, a magnetic flux collecting ring, and the like, and is configured such that the magnetic flux density changes according to the torsional displacement amount and the torsional displacement direction of the torsion bar. Since the general configuration of the torque sensor 83 is well known, detailed illustration of the configuration is omitted.

As shown in FIG. 2, the sensor unit 5 includes a main sensor unit 10 and a sub sensor unit 20.
The main sensor unit 10 includes a first main sensor element 11, a second main sensor element 12, A / D conversion circuits 13 and 14, a main output circuit 15, and a timing signal generation circuit 16. The sub sensor unit 20 includes a first sub sensor element 21, a second sub sensor element 22, A / D conversion circuits 23 and 24, and a sub output circuit 25. The first sub sensor element 21, the second sub sensor element 22, the A / D conversion circuits 23 and 24, and the sub output circuit 25 correspond to the corresponding first main sensor element 11, second main sensor element 12, and A / D conversion circuit. 13 and 14 and the main output circuit 15 are the same as those of the main output circuit 15. Therefore, the configuration of the main sensor unit 10 will be mainly described below, and the description of the sub sensor unit 20 will be omitted as appropriate.

The main sensor unit 10 is provided with a communication terminal 101. The communication terminal 101 is connected to the communication terminal 401 of the ECU 40 through the communication line 31. The sub sensor unit 20 is provided with a communication terminal 201. The communication terminal 201 is connected to the communication terminal 402 of the ECU 40 through the communication line 32.
The main sensor unit 10 and the sub sensor unit 20 are connected to the ECU 40 by a power line and a ground line (not shown), respectively. A voltage adjusted to a predetermined voltage (for example, 5 [V]) by a regulator (not shown) of the ECU 40 is supplied to the sensor units 10 and 20 via a power line. The sensor units 10 and 20 are connected to the ground via the ground line and the ECU 40.

The first main sensor element 11 and the second main sensor element 12 are magnetic detection elements that detect a change in magnetic flux of the magnetic flux collector 831 according to the steering torque. The first main sensor element 11 and the second main sensor element 12 of the present embodiment are Hall elements.
The A / D conversion circuit 13 A / D converts the detection value of the first main sensor element 11. The A / D conversion circuit 14 A / D converts the detection value of the second main sensor element 12.

The main output circuit 15 corresponds to the first main sensor signal corresponding to the detection value of the first main sensor element 11 subjected to A / D conversion and the detection value of the second main sensor element 12 subjected to A / D conversion. A main output signal Sm including the second main sensor signal is generated.
In the present embodiment, it is assumed that the main sensor elements 11 and 12 perform detection with a cycle shorter than the signal cycle Ps of the main output signal Sm, and the main output circuit 15 uses the latest detection value to detect the main output signal. Sm is generated. Similarly, the sub output circuit 25 generates the sub output signal Ss using the latest detection value.
The timing signal generation circuit 16 generates a timing signal St that instructs the output timing of the sub output signal Ss and outputs the timing signal St to the sub output circuit 25.

The sub output circuit 25 includes a first sub sensor signal corresponding to the detection value of the first sub sensor element 21 subjected to A / D conversion, and a second sub sensor corresponding to the detection value of the second sub sensor element 22 subjected to A / D conversion. A sub output signal Ss including the signal is generated. The sub output circuit 25 outputs the sub output signal Ss to the ECU 40 at the timing when the timing signal St is acquired.
In the present embodiment, the output signals Sm and Ss are output to the ECU 40 by SENT (Single Edge Nibble Transmission) communication which is a kind of digital communication.

Here, the communication frame of the main output signal Sm will be described with reference to FIG.
The main output signal Sm includes a synchronization signal, a status signal, a main sensor signal, a CRC signal, and a pause signal, and these signals are output as a series of signals in this order. The number of bits of each signal shown in the figure is an example, and is appropriately set according to a communication standard or the like. In SENT communication, data is expressed by the time width from the fall of each pulse to the next fall.

The synchronization signal is a signal for synchronizing the clocks of the main sensor unit 10 and the ECU 40, and is 56 ticks in the present embodiment. In the present embodiment, a correction coefficient is calculated based on the length of the synchronization signal, and each signal is corrected using the correction coefficient.
The status signal includes an update counter signal. For example, if the update counter signal is 2 bits, it is updated every time the main output signal Sm is generated, such as 00 → 01 → 10 → 11 → 00 → 01. Here, when the update counter reaches the maximum value (here, “11”), +1 is added to return to the minimum value (here, “00”). By transmitting the information of the update counter, the ECU 40 can determine whether the same data is transmitted because the detection value does not change from the previous time, or whether the data fixing abnormality has occurred.

  The main sensor signals are a first main sensor signal and a second main sensor signal. The first main sensor signal is a signal based on the detection value of the first main sensor element 11, and the second main sensor signal is a signal based on the detection value of the second main sensor element 12. In FIG. 3, the first main sensor signal is described as “Main1”, and the second main sensor signal is described as “Main2”. The first main sensor signal and the second main sensor signal are both 3 nibbles (= 12 bits). In the present embodiment, the main sensor signal and the sub sensor signal are nibble signals in order to output the main output signal Sm to the ECU 40 by SENT communication. The main sensor signal and the sub sensor signal may each be 1 nible or more, and are determined according to the communication specifications.

  In the present embodiment, one of the first main sensor signal and the second main sensor signal is a positive signal that increases as the detected value increases, and the other is an inverted signal that decreases as the detected value increases, and both are normal. If so, the added value becomes a predetermined added value. When the sum of the value of the first main sensor signal and the value of the second main sensor signal is different from the predetermined addition value, it is determined that a data abnormality has occurred. In FIG. 3, for the sake of simplicity, the first main sensor signal and the second main sensor signal are similarly described.

The CRC signal is a cyclic redundancy check signal for detecting a communication abnormality, and is a signal having a length calculated based on the first main sensor signal and the second main sensor signal.
The pause signal is a signal output during a period until the next synchronization signal is output.

The sub output signal Ss includes a synchronization signal, a status signal, a sub sensor signal, a CRC signal, and a pause signal. The sub sensor signals are a first sub sensor signal and a second sub sensor signal. The first sub sensor signal is a signal based on the detection value of the first sub sensor element 21, and the second sub sensor signal is a signal based on the detection value of the second sub sensor element 22.
Details of the communication frame of the sub output signal Ss are the same as those of the main output signal Sm, and thus the description thereof is omitted.

In this embodiment, the timing at which the output signals Sm and Ss are output is controlled by transmitting the timing signal St from the main sensor unit 10 to the sub sensor unit 20. The timing signal St is output from the timing signal generation circuit 16 to the sub output circuit 25 at any timing within one frame of the main output signal Sm. As shown in FIG. 4, in the present embodiment, the timing signal St is transmitted at the timing of a half cycle of one frame of the main output signal Sm. That is, the timing signal St is transmitted at a timing of (Ps / 2) from the start of the synchronization signal of the main output signal Sm. Thereby, the sub output circuit 25 outputs the sub output signal Ss at a timing shifted from the main output signal Sm by a half cycle.
The ECU 40 acquires the output signals Sm and Ss at the timing indicated by the arrow Y. That is, by shifting the output timing of the output signals Sm and Ss by a half cycle of the signal cycle Ps, the ECU 40 acquires the output signals Sm and Ss alternately every half cycle of the signal cycle Ps. Thereby, the apparent communication speed can be improved.

Returning to FIG. 2, the ECU 40 is configured mainly with a microcomputer or the like, and performs various arithmetic processes. Each process in the ECU 40 may be a software process by executing a program stored in advance by the CPU, or may be a hardware process by a dedicated electronic circuit.
ECU40 has the signal acquisition part 41, the abnormality detection part 42, the torque calculating part 43 as a physical-quantity calculating part, and the motor control part 45 as a functional block. These functional blocks are separated for convenience. For example, a part of processing of the abnormality detection unit 42 is executed by the torque calculation unit 43, and a part of processing described below is changed to different functional blocks. Can be executed.

The signal acquisition unit 41 includes a first acquisition unit 411 and a second acquisition unit 412. The first acquisition unit 411 acquires the main output signal Sm from the main output circuit 15, and corrects each signal included in the main output signal Sm with a correction coefficient calculated based on the synchronization signal. The second acquisition unit 412 acquires the sub output signal Ss from the sub output circuit 25 and corrects each signal included in the sub output signal Ss with a correction coefficient calculated based on the synchronization signal. Each corrected signal is output to the abnormality detection unit 42. The corrected sensor signal is output to the torque calculator 43.
The abnormality detection unit 42 detects an abnormality such as a data fixing abnormality, a data abnormality, a communication abnormality, and a power fault or a ground fault with respect to the main output signal Sm and the sub output signal Ss. The abnormality detection result is output to the torque calculation unit 43.

  The torque calculator 43 calculates a steering torque Tq that is a target physical quantity. Specifically, the main steering torque Tm as the main physical quantity is calculated using the main sensor signal of the main output signal Sm. For calculating the main steering torque Tm, one of the first main signal and the second main signal may be used, or a calculated value such as an average value of the first main signal and the second main signal may be used. In the present embodiment, if the main output signal Sm is normal, the steering torque Tq is set as the main steering torque Tm. That is, if the main output signal Sm is normal, the sensor signal of the sub output signal Ss is not used for the calculation of the steering torque Tq.

When the abnormality of the main output signal Sm is determined, the steering torque Tq is changed to a sub steering torque Ts as a sub physical quantity calculated using the sub sensor signal of the sub output signal Ss. In calculating the sub steering torque Ts, one of the first sub signal and the second sub signal may be used, or a calculated value such as an average value of the first sub signal and the second sub signal may be used.
The calculated steering torque Tq is output to the motor control unit 45.

  The motor control unit 45 controls driving of the motor 81 based on the calculated steering torque Tq. Specifically, the motor control unit 45 calculates a torque command value based on the steering torque Tq, and controls the driving of the motor 81 based on the torque command value by a known method such as feedback control.

  As described above, in the present embodiment, if the main output signal Sm is normal, the steering torque Tq is set to the main steering torque Tm, and if the main output signal Sm is abnormal, the steering torque Tq is switched to the sub steering torque Ts. The main steering torque Tm and the sub steering torque Ts may vary due to the influence of individual variation. Further, in the present embodiment, the output timing of the main output signal Sm and the output timing of the sub output signal Ss are shifted, and the sensor signals of the output signals Sm and Ss are based on detection values at different timings. Therefore, there is a possibility that the main steering torque Tm and the sub steering torque Ts vary due to the detection timing shift.

  Here, when the abnormality of the main output signal Sm is detected, if the steering torque Tq is directly switched from the main steering torque Tm to the sub steering torque Ts, the steering torque Tq may change sharply. In the present embodiment, since the sensor device 1 is applied to the electric power steering device 80, when the steering torque Tq changes abruptly, the fluctuation of the auxiliary torque output from the motor 81 becomes large, giving the driver a sense of incongruity. There is a fear.

In the present embodiment, in order to prevent erroneous determination, the abnormality is not determined and monitoring is continued for a predetermined period after the abnormality of the main output signal Sm is detected.
Therefore, in the present embodiment, the torque calculation unit 43 determines the sub steering torque Ts and the main steering torque Tm before the abnormality is detected in the undetermined period from when the abnormality of the main output signal Sm is detected until the abnormality is determined. Is used to calculate the steering torque Tq.

  The torque calculation process in this embodiment is demonstrated based on the flowchart shown in FIG. This process is executed when the ECU 40 is being activated and the main output signal Sm is acquired. That is, the calculation cycle of the torque calculation process is equal to the signal cycle Ps. Hereinafter, unless otherwise stated, the latest main output signal Sm or sub output signal Ss is used. In the present embodiment, the acquisition timing of the output signals Sm and Ss is shifted by a half cycle (Ps / 2), so that the sub output signal Ss acquired before the half cycle (Ps / 2) is used. become.

  In the first step S101, the abnormality detection unit 42 determines whether an abnormality of the main output signal Sm has been detected. Hereinafter, “Step” in Step S101 is omitted and described as “S101”. The other steps are the same. When it is determined that an abnormality in the main output signal Sm is detected (S101: YES), the process proceeds to S104. At this stage, no abnormality has been confirmed. When it is determined that the abnormality of the main output signal Sm is not detected (S101: NO), information indicating that the main output signal Sm is normal is output to the torque calculator 43, and the process proceeds to S102.

In S102, it is considered that the main output signal Sm is normal, and the torque calculation unit 43 sets the steering torque Tq as the main steering torque Tm calculated based on the sensor signal of the main output signal Sm.
In S103, the torque calculation unit 43 stores the main steering torque Tm in a memory (not shown) of the ECU 40 as the main steering torque hold value Tm_h. The memory of this embodiment is a RAM (Random Access Memory). Thereby, the main steering torque holding value Tm_h is held. The main steering torque holding value Tm_h may be overwritten for each calculation, as long as the latest value is held.

In S104, where an abnormality of the main output signal Sm is detected (S101: YES), the abnormality detection unit 42 determines whether an abnormality of the sub output signal Ss is detected. When the abnormality of the sub output signal Ss is detected (S104: YES), the processing after S105 is not performed. That is, when an abnormality is detected in the main output signal Sm and the sub output signal Ss, the torque calculation is not performed. If the abnormality of the main output signal Sm and the sub output signal Ss is confirmed, the electric power steering device 80 is stopped because of a double failure. For example, the previous value is held as the steering torque Tq during the period from the detection of the double failure to the determination.
When it is determined that the abnormality of the sub output signal Ss is not detected (S104: NO), the sub output signal Ss is regarded as normal, and the process proceeds to S105.

In S105, the abnormality detection unit 42 increments the count value C1 of the abnormality confirmation counter related to the abnormality confirmation of the main output signal Sm.
In S106, the abnormality detection unit 42 determines whether or not the count value C1 is larger than the abnormality determination threshold Cth1. When it is determined that the count value C1 is equal to or less than the abnormality confirmation threshold Cth1 (S106: NO), information indicating that the abnormality is not established until the abnormality is confirmed after the abnormality of the main output signal Sm is detected is torqued. The result is output to the calculation unit 43 and the process proceeds to S108. When it is determined that the count value C1 is larger than the abnormality confirmation threshold Cth1 (S106: YES), information indicating that the abnormality of the main output signal Sm is confirmed is output to the torque calculation unit 43, and the process proceeds to S107.

  In S107, after the abnormality of the main output signal Sm is determined, the torque calculation unit 43 sets the steering torque Tq as the sub steering torque Ts calculated based on the sensor signal of the sub output signal Ss.

When the abnormality of the main output signal Sm is detected and the count value C1 is equal to or less than the abnormality determination threshold Cth1 (S101: YES and S106: NO), the process proceeds to S108, where the abnormality of the main output signal Sm is detected. This is the indeterminate period until it is confirmed. The torque calculation unit 43 calculates the steering torque Tq with the formula (1) based on the main steering torque holding value Tm_h and the sub steering torque Ts held in the memory. In the equation, r corresponds to the first transition coefficient, and (1-r) corresponds to the second transition coefficient. The first transition coefficient r is appropriately set within the range of 0 <r <1.
Tq = Tm_h × r + Ts × (1-r) (1)

  In the present embodiment, the torque calculation unit 43 has a main steering torque holding value Tm_h that is the main steering torque Tm before the abnormality is detected in the undetermined period from when the abnormality of the main output signal Sm is detected until the abnormality is confirmed. And the steering torque Tq is calculated using the latest sub steering torque Ts. Further, when the abnormality of the main output signal Sm is determined, the steering torque Tq is switched to the sub steering torque Ts. As a result, when an abnormality in the main output signal Sm is detected, it is possible to suppress fluctuations in the steering torque Tq compared to the case where the steering torque Tq is directly changed from the main steering torque Tm to the sub steering torque Ts. it can.

As described above, the sensor device 1 according to the present embodiment includes the main sensor unit 10, the sub sensor unit 20, and the ECU 40.
The main sensor unit 10 includes main sensor elements 11 and 12 and a main output circuit 15. The main sensor elements 11 and 12 detect the target physical quantity (the magnetic flux of the magnetism collecting unit 831 in this embodiment). The main output circuit 15 generates and outputs a main output signal Sm including a main sensor signal corresponding to the detection values of the main sensor elements 11 and 12.

  The sub sensor unit 20 includes sub sensor elements 21 and 22 and a sub output circuit 25. The sub sensor elements 21 and 22 detect the target physical quantity. The sub output circuit 25 generates a sub output signal Ss including a sub sensor signal corresponding to the detection values of the sub sensor elements 21 and 22, and is shifted from the main output signal Sm for a predetermined period shorter than the length of one cycle of the signal cycle Ps. To output the sub output signal Ss.

  The ECU 40 includes a signal acquisition unit 41, an abnormality detection unit 42, and a torque calculation unit 43. The signal acquisition unit 41 acquires the main output signal Sm and the sub output signal Ss. The abnormality detection unit 42 detects an abnormality in the main output signal Sm and the sub output signal Ss. The torque calculator 43 calculates the steering torque Tq based on at least one of the main sensor signal and the sub sensor signal.

When the main output signal Sm is normal, the torque calculation unit 43 sets the main steering torque Tm calculated based on the main sensor signal as the steering torque Tq.
In addition, the torque calculation unit 43 detects the sub steering torque Ts calculated based on the sub sensor signal and the abnormality in the undetermined period from when the abnormality of the main output signal Sm is detected until the abnormality is confirmed. The steering torque Tq is calculated based on the main steering torque Tm before starting.

  The sensor device 1 of the present embodiment includes the main sensor unit 10 and the sub sensor unit 20, and the signal acquisition unit 41 can acquire the main output signal Sm and the sub output signal Ss. However, the calculation of the steering torque Tq can be continued. Further, the steering torque Tq during the undetermined period is calculated based on the sub steering torque Ts and the main steering torque Tm before the abnormality is detected. As a result, when an abnormality occurs in a part of the signals, it is possible to suppress fluctuations in the steering torque Tq accompanying switching to calculation using a normal signal.

When the abnormality of the main output signal Sm is determined, the torque calculation unit 43 sets the sub steering torque Ts as the steering torque Tq.
In the present embodiment, the torque calculation unit 43 calculates the steering torque Tq during the undetermined period based on the sub steering torque Ts calculated based on the sub sensor signal and the main steering torque Tm before the abnormality is detected. doing. Therefore, when the main output signal Sm is abnormal, the fluctuation of the steering torque Tq can be suppressed as compared with the case where the steering torque Tq is directly switched from the main steering torque Tm to the sub steering torque Ts.

The torque calculation unit 43 calculates a value obtained by multiplying the main steering torque Tm before the abnormality of the main output signal Sm is detected by the first transition coefficient r that is greater than or equal to 0 and less than 1 and the latest sub-steering torque in the undetermined period. A sum of a value obtained by multiplying Ts by the second transition coefficient (1-r) is defined as a steering torque Tq.
As a result, the steering torque Tq during the undetermined period can be calculated with a relatively simple calculation.

  The main sensor elements 11 and 12 and the sub sensor elements 21 and 22 are magnetic detection elements that detect the magnetic flux of the magnetism collecting unit 831 as a target physical quantity. The main sensor elements 11 and 12 and the sub sensor elements 21 and 22 detect a change in magnetic flux that changes according to torque. Thereby, torque (steering torque in this embodiment) can be detected appropriately.

The electric power steering device 80 includes the sensor device 1, a motor 81, and a reduction gear 82. The motor 81 outputs an auxiliary torque that assists the steering of the steering wheel 91 by the driver. The reduction gear 82 transmits the torque of the motor 81 to the steering shaft 92 that is a driving target.
The torque calculator 43 calculates the steering torque Tq.
The ECU 40 includes a motor control unit 45 that controls the driving of the motor 81 based on the steering torque Tq.

Since the ECU 40 includes the main sensor unit 10 and the sub sensor unit 20, even when an abnormality occurs in one of the ECUs 40, the calculation of the steering torque Tq can be continued using the other. Thereby, the electric power steering apparatus 80 can continue assisting steering according to the steering torque Tq. Further, during the undetermined period, the torque calculator 43 calculates the steering torque Tq using the sub steering torque Ts and the main steering torque Tm before the abnormality is detected. Thereby, since the fluctuation | variation of the steering torque Tq is suppressed, the torque fluctuation | variation of the motor 81 controlled based on the steering torque Tq is also suppressed. Thereby, since the fluctuation | variation of the assist force by the electric power steering apparatus 80 is suppressed, the uncomfortable feeling given to a driver | operator can be reduced.
In the present embodiment, the steering torque Tq corresponds to the “target physical quantity”, the main steering torque Tm corresponds to the “main physical quantity”, and the sub steering torque Ts corresponds to the “sub physical quantity”.

(Second Embodiment)
A second embodiment of the present invention is shown in FIG. In the second to fifth embodiments, torque calculation processing is different from that of the above-described embodiment, and this point will be mainly described. Hereinafter, the steering torque Tq calculated in the immediately preceding calculation is referred to as the previous steering torque Tq (n−1).
The torque calculation process of this embodiment is demonstrated based on the flowchart shown in FIG. The calculation cycle and the like are the same as those in the above embodiment.
The processing of S201 to S207 is the same as the processing of S101 to S107 in FIG. When it is determined in S206 that the count value C1 is equal to or less than the abnormality confirmation threshold Cth1 (S206: NO), the process proceeds to S208.

  In S208, the abnormality detection unit 42 determines whether or not the first calculation after the abnormality of the main output signal Sm is detected. When it is determined that the calculation is not the first calculation (S208: NO), that is, when the count value C1 is 2 or more and the abnormality determination threshold Cth1 or less, information indicating that the calculation is not the first calculation is output to the torque calculation unit 43, and the process proceeds to S210. Transition. When it is determined that the calculation is the first calculation (S208: YES), that is, when the count value C1 is 1, information indicating the first calculation is output to the torque calculation unit 43, and the process proceeds to S209.

In S209, the torque calculator 43 calculates the steering torque Tq based on the main steering torque hold value Tm_h and the sub steering torque Ts, which are the previous steering torque Tq (n−1) (see Expression (2)). In the equation, k corresponds to the first transition coefficient, and (1-k) corresponds to the second transition coefficient. The first transition coefficient k is appropriately set within the range of 0 <k <1.
Tq = Tm_h × k + Ts × (1−k) (2)

In S210, the process proceeds to the second or subsequent calculation after the abnormality of the main output signal Sm is detected (S208: NO), the torque calculation unit 43 holds the steering torque that is the previous steering torque Tq (n-1). Based on the value Tq_h and the sub steering torque Ts, the steering torque Tq is calculated (see Expression (3)).
Tq = Tq_h × k + Ts × (1-k) (3)

  In S211, which is shifted from S209 or S210, the torque calculation unit 43 stores the value calculated in S209 or S210 in the memory as the steering torque holding value Tq_h. Thereby, the steering torque holding value Tq_h is held. The steering torque holding value Tq_h may be overwritten for each calculation as long as the latest value is held. The same applies to a steering torque holding value Tq_h in an embodiment described later.

  In the present embodiment, the processing of S208 to S211 is performed in an undetermined period from when the abnormality of the main output signal Sm is detected until it is determined. That is, the torque calculator 43 calculates the steering torque Tq using the previous steering torque Tq (n−1) and the latest sub steering torque Ts during the undetermined period. As a result, the steering torque Tq gradually approaches the sub-steering torque Ts during the undetermined period, so that fluctuations in the steering torque Tq associated with switching of signals used for calculating the steering torque Tq can be further suppressed.

In the present embodiment, the torque calculation unit 43 is a first transition coefficient to the main steering torque Tm before the abnormality is detected in the initial calculation after the abnormality of the main output signal Sm is detected during the undetermined period. The sum of the value obtained by multiplying k and the value obtained by multiplying the latest sub steering torque Ts by the second transition coefficient (1-k) is defined as the steering torque Tq.
In addition, the torque calculation unit 43 calculates the value obtained by multiplying the steering torque holding value Tq_h, which is the previous steering torque Tq (n−1), by the first transition coefficient k and the latest sub The sum of the value obtained by multiplying the steering torque Ts by the second transition coefficient (1-k) is defined as the steering torque Tq. If it is assumed that the initial calculation after the abnormality detection of the steering torque Tq is performed using the main steering torque Tm before the abnormality detection, the second and subsequent steering torques Tq are calculated using the previous value of the steering torque Tq. This is included in the concept of “calculating the target physical quantity using the main physical quantity before the abnormality is detected”.
As a result, the steering torque Tq during the undetermined period can be made asymptotic to the sub steering torque Ts, so that fluctuations in the steering torque Tq can be suppressed.
In addition, the same effects as those of the above embodiment can be obtained.

(Third embodiment)
A torque calculation process according to the third embodiment of the present invention will be described based on a flowchart shown in FIG.
The processing of S301 to S307 is the same as S101 to S107 in FIG. When it is determined in S306 that the count value C1 is equal to or less than the abnormality determination threshold Cth1 (S306: NO), the process proceeds to S308.

  In S308, as in S208, the abnormality detection unit 42 determines whether or not this is the first calculation after the abnormality of the main output signal Sm is detected. When it is determined that the calculation is not the first calculation (S308: NO), that is, when the count value C1 is 2 or more and the abnormality determination threshold Cth1 or less, information indicating that the calculation is not the first calculation is output to the torque calculation unit 43, and the process proceeds to S313. Transition. When it is determined that the calculation is the first calculation (S308: YES), that is, when the count value C1 is 1, information indicating that the calculation is the first calculation is output to the torque calculation unit 43, and the process proceeds to S309.

In S309, the torque calculator 43 calculates the initial transition asymptotic value Va1 (see Expression (4)). The initial transition asymptotic value Va1 is a value based on a difference value between the main steering torque holding value Tm_h, which is the previous steering torque Tq (n−1), and the sub steering torque Ts. Further, z1 in the formulas (4) and (7) is 0 <z1 <1.
Va1 = | Tm_h−Ts | × z1 (4)

  In S310, the torque calculation unit 43 determines whether the main steering torque hold value Tm_h is equal to or greater than the sub steering torque Ts. When it is determined that the main steering torque hold value Tm_h is equal to or greater than the sub steering torque Ts (S310: YES), the process proceeds to S311. When it is determined that the main steering torque hold value Tm_h is smaller than the sub steering torque Ts (S310: NO), the process proceeds to S312.

In S311, the torque calculation unit 43 sets a value obtained by subtracting the initial transition asymptotic value Va1 from the main steering torque holding value Tm_h as the steering torque Tq (see Expression (5)).
Tq = Tm_h−Va1 (5)
In S312, the torque calculation unit 43 sets a value obtained by adding the initial transition asymptotic value Va1 to the main steering torque holding value Tm_h as the steering torque Tq (see Expression (6)).
Tq = Tm_h + Va1 (6)

In S313, which is shifted to the case where it is determined that the calculation is not the first calculation (S308: NO), the torque calculation unit 43 calculates the transition asymptotic value Va2 (see Expression (7)). The transition asymptotic value Va2 is a value based on the difference value between the steering torque holding value Tq_h, which is the previous steering torque Tq (n−1), and the sub steering torque Ts.
Va2 = | Tq_h−Ts | × z1 (7)

  In S314, the torque calculator 43 determines whether or not the steering torque holding value Tq_h is equal to or greater than the sub steering torque Ts. When it is determined that the steering torque holding value Tq_h is equal to or greater than the sub steering torque Ts (S314: YES), the process proceeds to S315. When it is determined that the steering torque holding value Tq_h is smaller than the sub steering torque Ts (S314: NO), the process proceeds to S316.

In S315, the torque calculation unit 43 sets the value obtained by subtracting the transition asymptotic value Va2 from the steering torque holding value Tq_h as the steering torque Tq (see Expression (8)).
Tq = Tq_h−Va2 (8)
In S316, the torque calculation unit 43 sets a value obtained by adding the transition asymptotic value Va2 to the steering torque holding value Tq_h as the steering torque Tq (see Expression (9)).
Tq = Tq_h + Va2 (9)

  In S317, which is shifted to S311, S312, S315, or S316, the torque calculation unit 43 stores the value calculated in S311, S312, S315, or S316 in the memory as the steering torque holding value Tq_h. Thereby, the steering torque holding value Tq_h is held.

In the present embodiment, the processes of S308 to S317 are performed in the undetermined period from when the abnormality of the main output signal Sm is detected until it is determined. That is, the torque calculation unit 43 calculates asymptotic values Va1 and Va2 based on the difference value between the previous steering torque Tq (n−1) and the latest sub steering torque. When the latest sub steering torque Ts is smaller than the previous steering torque Tq (n−1), the asymptotic values Va1 and Va2 are subtracted from the previous steering torque Tq (n−1), and the latest sub steering torque Ts is steered last time. When the torque is equal to or greater than the torque Tq (n−1), the asymptotic values Va1 and Va2 are added to the previous steering torque Tq (n−1). In other words, whether to add or subtract asymptotic values Va1 and Va2 is determined according to the magnitude relationship between the sub steering torque Ts and the previous steering torque Tq (n−1).
As a result, the steering torque Tq gradually approaches the sub-steering torque Ts during the undetermined period, so that fluctuations in the steering torque Tq associated with switching of signals used for calculating the steering torque Tq can be further suppressed.

  In the present embodiment, the torque calculation unit 43 is the uncertain period, and the main steering torque Tm before the abnormality is detected and the latest sub-steering in the initial calculation after the abnormality of the main output signal Sm is detected. A value based on a difference value from the torque Ts is set as an initial transition asymptotic value Va1, and the steering torque Tq is calculated using the initial transition asymptotic value Va1. Specifically, the steering torque Tq is calculated based on the main steering torque holding value Tm_h that is the main steering torque Tm before the abnormality is detected and the initial transition asymptotic value Va1.

In addition, in the second and subsequent calculations in the undetermined period, the torque calculation unit 43 sets a value based on the difference value between the steering torque Tq calculated last time and the latest sub-steering torque Ts as the transition asymptotic value Va2, and the transition asymptotic value. The steering torque Tq is calculated using Va2. Specifically, the steering torque Tq is calculated based on the steering torque holding value Tq_h that is the previous steering torque Tq (n−1) and the transition asymptotic value Va2.
As a result, the steering torque Tq during the undetermined period can be made asymptotic to the sub steering torque Ts, so that fluctuations in the steering torque Tq can be suppressed.
In addition, the same effects as those of the above embodiment can be obtained.

(Fourth embodiment)
A torque calculation process according to the fourth embodiment of the present invention will be described based on a flowchart shown in FIG.
The process of S401 is the same as the process of S101 in FIG. If an affirmative determination is made in S401, a count value C2 of a normal return counter described later is reset.
In S402, the abnormality detection unit 42 determines whether or not the count value C1 of the abnormality confirmation counter is zero. When it is determined that the count value C1 is not 0 (S402: NO), the process proceeds to S411. When it is determined that the count value C1 is 0 (S402: YES), the process proceeds to S403.

The processing of S403 to S409 is the same as the processing of S102 to S108. Although FIG. 8 shows an example in which the steering torque Tq during the undetermined period is calculated by Expression (1) as in the first embodiment, S208 to S210 in the second embodiment may be used instead of S409. And it is good also as S308-S316 of a 3rd embodiment.
In S410, the torque calculation unit 43 stores the calculated steering torque Tq in the memory as the steering torque holding value Tq_h.

In S411, where the abnormality is not detected in the main output signal Sm and it is determined that the count value C1 of the abnormality confirmation counter is not 0 (S401: NO and S402: NO), the abnormality detection unit 42 Then, the count value C2 of the normal return counter is incremented.
In S412, the abnormality detection unit 42 determines whether or not the count value C2 is greater than the return completion threshold Cth2. When it is determined that the count value C2 is equal to or less than the return completion threshold Cth2 (S412: NO), information indicating that it is a return standby period is output to the torque calculation unit 43, and the process proceeds to S415. When it is determined that the count value C2 is larger than the return completion threshold Cth2, information on normal return completion is output to the torque calculation unit 43, and the process proceeds to S413.

In S413, although the abnormality of the main output signal Sm is temporarily detected, the state in which the main output signal Sm is normal is continued during the return waiting period, so that the main output signal Sm is considered to have returned to normal. Then, the torque calculation unit 43 sets the steering torque Tq as the main steering torque Tm. Further, the torque calculation unit 43 resets the count values C1 and C2.
In S414, the torque calculation unit 43 stores the calculated main steering torque Tm in the memory as the main steering torque hold value Tm_h, as in S404. Thereby, the main steering torque holding value Tm_h is held.

In S415, when the count value C2 is determined to be equal to or less than the return completion threshold Cth2 (S412: NO), the torque calculator 43 determines that the steering torque holding value Tq_h, which is the previous steering torque Tq (n−1), and Based on the main steering torque Tm, the steering torque Tq is calculated (see equation (10)). In the equation, j corresponds to the first return coefficient, and (1-j) corresponds to the second return coefficient. The first return coefficient j is appropriately set within the range of 0 <j <1.
Tq = Tq_h * j + Tm * (1-j) (10)
In S416, the torque calculation unit 43 stores the value calculated in S414 in the memory as the steering torque hold value Tq_h. Thereby, the steering torque holding value Tq_h is held.

  In the present embodiment, the processes of S411 to S416 are performed in the return waiting period. That is, when an abnormality is temporarily detected after the abnormality is temporarily detected in the main output signal Sm, the torque calculation unit 43 performs steering that is the previous steering torque Tq (n−1) during the return waiting period when the abnormality is resolved and normal recovery is performed. The steering torque Tq is calculated using the torque holding value Tq_h and the main steering torque Tm. As a result, when returning to normal, fluctuations in the steering torque Tq can be suppressed as compared with a case where the steering torque Tq calculated using the sub steering torque Ts is directly changed to the main steering torque Tm.

In the present embodiment, when the main output signal Sm becomes normal after the abnormality of the main output signal Sm is detected, the torque calculation unit 43 performs the previous steering torque Tq during the return waiting time until the normal return is determined. The sum of the value obtained by multiplying (n-1) by the first return coefficient j and the value obtained by multiplying the latest main steering torque Tm by the second return coefficient (1-j) is defined as the steering torque Tq.
As a result, the steering torque Tq can be made asymptotically closer to the main steering torque Tm during the normal return period, so that fluctuations in the steering torque Tq when returning to normal can be suppressed.
In addition, the same effects as those of the above embodiment can be obtained.

(Fifth embodiment)
A torque calculation process according to the fifth embodiment of the present invention will be described with reference to a flowchart shown in FIG.
The processing of S501 to S514 is the same as the processing of S401 to S414 in FIG. If it is determined in S512 that the count value C2 is equal to or less than the return completion threshold Cth2 (S512: NO), the process proceeds to S515.
In S515, the torque calculator 43 calculates the return asymptotic value Vb (see Expression (11)). The return asymptotic value Vb is a value based on the difference value between the steering torque holding value Tq_h, which is the previous steering torque Tq (n−1), and the main steering torque Tm. Z2 in the formula (11) is 0 <z2 <1.
Vb = | Tq_h−Tm | × z2 (11)

  In S516, the torque calculation unit 43 determines whether or not the steering torque holding value Tq_h that is the previous steering torque Tq (n−1) is equal to or greater than the main steering torque Tm. When it is determined that the steering torque hold value Tq_h is equal to or greater than the main steering torque Tm (S516: YES), the process proceeds to S517. When it is determined that the steering torque holding value Tq_h is smaller than the main steering torque Tm (S516: NO), the process proceeds to S518.

In S517, the torque calculation unit 43 sets the value obtained by subtracting the return asymptotic value Vb from the steering torque holding value Tq_h as the steering torque Tq (see Expression (12)).
Tq = Tq_h−Vb (12)
In S518, the torque calculation unit 43 sets a value obtained by adding the return asymptotic value Vb to the steering torque holding value Tq_h as the steering torque Tq (see Expression (13)).
Tq = Tq_h + Vb (13)
In S519, which is shifted to S517 or S518, the value calculated in S517 or S518 is stored in the memory as the steering torque holding value Tq_h. Thereby, the steering torque holding value Tq_h is held.

In the present embodiment, the processes of S515 to S519 are performed in the return waiting period. That is, the torque calculator 43 calculates the return asymptotic value Vb based on the difference value between the previous steering torque Tq (n−1) and the latest main steering torque Tm. When the latest main steering torque Tm is smaller than the previous steering torque Tq (n−1), the return asymptotic value Vb is subtracted from the previous steering torque Tq (n−1), so that the latest main steering torque Tm is the previous steering torque. When it is equal to or greater than Tq (n−1), the return asymptotic value Vb is added to the previous steering torque Tq (n−1). In other words, it is determined whether to add or subtract the return asymptotic value Vb according to the magnitude relationship between the main steering torque Tm and the previous steering torque Tq (n−1).
As a result, the steering torque Tq gradually approaches the main steering torque Tm during the return standby period, so that fluctuations in the steering torque Tq associated with switching of signals used for calculating the steering torque Tq can be suppressed.

In the present embodiment, when the main output signal Sm becomes normal after the abnormality of the main output signal Sm is detected, the torque calculation unit 43 performs the previous steering torque Tq in the return waiting period until the normal return is determined. A value based on a difference value between (n−1) and the latest main steering torque Tm is set as a return asymptotic value Vb, and the steering torque Tq is calculated using the return asymptotic value Vb. Specifically, the torque calculator 43 calculates the steering torque Tq based on the steering torque holding value Tq_h and the return asymptotic value Vb, which are the previous steering torque Tq (n−1).
As a result, the steering torque Tq can be made asymptotically closer to the main steering torque Tm during the normal return period, so that fluctuations in the steering torque Tq when returning to normal can be suppressed.
In addition, the same effects as those of the above embodiment can be obtained.

(Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 10, the sensor device 2 of the present embodiment includes a sensor unit 5, an ECU 50 as a control unit, and the like. The ECU 50 includes a differential calculation unit 47 and an integral calculation unit 48 in addition to the signal acquisition unit 41, the abnormality detection unit 42, the torque calculation unit 43 as a physical quantity calculation unit, and the motor control unit 45.
The differential calculation unit 47 and the integration calculation unit 48 obtain the main steering torque Tm and the sub steering torque Ts from the torque calculation unit 43.

The differential calculation unit 47 calculates a main differential value dTm that is a differential value of the main steering torque Tm and a sub differential value dTs that is a differential value of the sub steering torque Ts. When the current value of the main steering torque Tm is Tm (n) and the previous value is Tm (n−1), the main differential value dTm is calculated by the equation (14).
dTm = {Tm (n) −Tm (n−1)} / Ps (14)
Further, when the current value of the sub steering torque Ts is Ts (n) and the previous value is Ts (n−1), the sub differential value dTs is calculated by the equation (15).
dTs = {Ts (n) −Ts (n−1)} / Ps (15)

When the main output signal Sm is normal, the differential calculation unit 47 sets the main differential value dTm as the torque differential value dTq and holds the main differential value dTm in the memory. While the main output signal Sm is normal, the calculation of the sub differential value dTs may be omitted.
When the abnormality of the main output signal Sm is determined, the torque differential value dTq is switched to the sub differential value dTs. Further, in the undetermined period from when the abnormality of the main output signal Sm is detected until the abnormality is confirmed, the torque differential value is based on the main differential value dTm and the latest sub differential value dTs before the abnormality is detected. dTq is calculated.

The integration calculation unit 48 calculates a main integration value iTm that is an integration value of the main steering torque Tm and a sub integration value iTs that is an integration value of the sub steering torque Ts. The main integration value iTm and the sub-integration value iTs are calculated by equations (16) and (17).
iTm = {Tm (n) + Tm (n−1)} × Ps (16)
iTs = {Ts (n) + Ts (n−1)} × Ps (17)

When the main output signal Sm is normal, the integration calculation unit 48 sets the main integration value iTm as the torque integration value iTq and holds the main integration value iTm in the memory. Note that while the main output signal Sm is normal, the calculation of the sub-integration value iTs may be omitted.
When the abnormality of the main output signal Sm is determined, the torque integral value iTq is switched to the sub-integration value iTs. Further, in the undetermined period from when the abnormality of the main output signal Sm is detected until the abnormality is confirmed, the torque integrated value is based on the main integrated value iTm and the latest sub-integrated value iTs before the abnormality is detected. iTq is calculated.
The calculated torque differential value dTq and the torque integral value iTq can be used for various calculations in addition to the calculation in the motor control unit 45.

By replacing the main steering torque Tm of the above embodiment with the main differential value dTm and the sub steering torque Ts with the sub differential value dTs, the torque differential value dTq is replaced with the steering torque Tq, similarly to the above embodiment. It can be calculated.
Further, the main integrated torque iTm is replaced with the main steering torque Tm in the above embodiment, and the sub integrated value iTs is replaced with the sub steering torque Ts, whereby the torque integrated value iTq is replaced with the steering torque Tq. The same calculation can be performed.

  When the abnormality of the main output signal Sm is detected, in the configuration in which the previous steering torque Tq (n−1) is held as the steering torque Tq, the difference between the previous value and the current value is 0, so the torque differential value dTq Is also 0. For example, in the configuration in which the steering torque Tq is the main steering torque Tm when the main output signal Sm is normal, the previous steering torque Tq (n−1) is during the undetermined period, and the sub steering torque Ts is after the abnormality is determined, the undetermined period. Therefore, the torque differential value dTq may change sharply before and after the undetermined period.

  In the present embodiment, the differential calculation unit 47 calculates the torque differential value dTq using the main differential value dTm and the sub differential value dTs before abnormality detection in the undetermined period, so that the torque differential value dTq in the undetermined period is 0. In other words, the fluctuation of the torque differential value dTq before and after the undetermined period is suppressed. Further, compared with a case where the main differential value dTm is directly switched to the sub differential value dTs, the fluctuation of the torque differential value dTq can be suppressed.

  In the configuration in which the previous steering torque Tq (n−1) is held as the steering torque Tq during the undetermined period, the torque integrated value iTq during the undetermined period is constant. There is a risk of steep fluctuations. In the present embodiment, the torque integral value iTq is calculated using the main integral value iTm and the sub-integral value iTs in the normal period during the uncertain period. Variations in the torque integral value iTq before and after the fixed period are suppressed. Further, compared to a case where the main integral value iTm is directly switched to the sub-integral value iTs, etc., fluctuations in the torque integral value iTq can be suppressed.

Further, the differential calculation unit 47 may calculate the torque differential value dTq during the normal return period using the previous value dTq (n−1) and the main differential value dTm as in the fifth embodiment. Thereby, it is possible to suppress a steep change in the torque differential value dTq at the time of normal return.
Similarly, the integral calculation unit 48 may calculate the torque integrated value iTq during the normal return period using the previous value iTq (n−1) and the main integrated value iTm. Thereby, the fluctuation | variation of the torque integral value iTq at the time of a normal return can be suppressed.

The ECU 50 includes a differential calculation unit 47 that calculates a torque differential value dTq that is a differential value of the steering torque Tq. When the main output signal Sm is normal, the differential operation unit 47 sets the main differential value dTm, which is the differential value of the main steering torque Tm, as the torque differential value dTq. Further, the differential calculation unit 47 calculates a torque differential value dTq based on the sub steering torque Ts and the main steering torque Tm before the abnormality is detected in the undetermined period. The calculation of the torque differential value dTq based on the sub differential value dTs and the main differential value dTm before the abnormality is detected is based on “the sub physical quantity and the main physical quantity before the abnormality is detected. It is included in the concept of “calculating a differential value of a target physical quantity”.
Thereby, the fluctuation | variation of the torque differential value dTq accompanying the switch to the calculation using a normal signal can be suppressed.

Further, the ECU 50 has an integral calculation unit 48 that calculates a torque integral value iTq that is an integral value of the steering torque Tq. When the main output signal Sm is normal, the integral calculation unit 48 sets the main integral value iTm, which is an integral value of the main steering torque Tm, as the torque integral value iTq. Further, the integral calculation unit 48 calculates a torque integral value based on the sub steering torque Ts and the main steering torque Tm before the abnormality is detected in the undetermined period. The calculation of the torque integral value iTq based on the sub-integral value iTs and the main integral value iTm before the abnormality is detected is based on “the sub-physical quantity and the main physical quantity before the abnormality is detected. It is included in the concept of “calculating an integral value of a target physical quantity”.
Thereby, the fluctuation | variation of the torque integral value iTq accompanying the switch to the calculation using a normal signal can be suppressed.
In addition, the same effects as those of the above embodiment can be obtained.

(Other embodiments)
(A) Main sensor unit and sub sensor unit In the above embodiment, the sensor device is provided with one main sensor unit and one sub sensor unit. In another embodiment, the sensor device may be provided with a plurality of at least one of the main sensor unit and the sub sensor unit. In the above embodiment, the main sensor unit and the cebu sensor unit are provided separately. In another embodiment, the main sensor part and the sub sensor part may be sealed with one sealing part and may be one package.
In the above embodiment, two sensor elements are provided in the main sensor unit and the sub sensor unit. In other embodiments, the number of sensor elements provided in the main sensor unit may be one, or may be three or more. The same applies to the sub sensor unit. Moreover, the number of sensor elements of the main sensor unit and the Cebu sensor unit may be different.

In the above embodiment, the sensor element is a Hall element. In other embodiments, the sensor element may be a magnetic detection element other than a Hall element, or may be an element that detects a physical quantity other than magnetism.
Moreover, in the said embodiment, a main sensor part and a sub sensor part are used for the torque sensor which detects steering torque. In other embodiments, the sensor unit may detect any physical quantity such as torque other than steering torque, rotation angle, stroke, weight, pressure, and the like.

(A) Output signal In the said embodiment, a main output circuit outputs a main output signal to a control part by SENT communication. In another embodiment, the main output circuit may output the main output signal to the control unit by a digital communication method other than SENT communication. The main output circuit may output a main output signal to the control unit by analog communication. The same applies to the sub output circuit.

In the above embodiment, the sub output signal is output by shifting the main output signal by a half period of the signal period. In another embodiment, the shift width of the output timing between the main output signal and the sub output signal is not limited to a half cycle of the signal cycle, and may be a predetermined period shorter than one cycle of the signal cycle. In addition, if there are three or more output signals (main output signal or sub output signal) output to the control unit, the control unit shifts the output signal by the period obtained by dividing the signal period by the number of signals, and the like. It can be acquired at intervals, and the apparent communication speed can be improved.
Alternatively, a predetermined period related to the output timing deviation between the main output signal and the sub output signal may be set as short as possible, and the main output signal and the sub output signal may be output to the control unit substantially simultaneously.

In the above embodiment, the timing signal generation circuit is provided in the main sensor unit. In another embodiment, a timing signal generation circuit may be provided in the sub sensor unit, or the timing signal generation circuit may not be provided, and the main sensor unit and the sub sensor unit may output an output signal to the control unit at each timing. Good.
Further, a request signal output unit may be provided in the control unit, and the main output signal and the sub output signal may be output according to the request signal output from the request signal output unit. Thus, the control unit can acquire the main output signal and the sub output signal at a desired timing.

(C) Control Unit In the above embodiment, the physical quantity calculation unit is a torque calculation unit that calculates the steering torque, and calculates the steering torque using at least one of the main steering torque and the sub steering torque. In another embodiment, the target physical quantity, the main physical quantity, and the sub physical quantity may be voltage values output from the sensor element, and the voltage value calculated as the target physical quantity may be torque converted. Further, the target physical quantity, the main physical quantity, and the sub physical quantity may be physical quantities other than torque.

  In the above embodiment, the torque calculation unit performs the torque calculation process at the timing when the main output signal is acquired. In another embodiment, the torque calculation unit may perform the torque calculation process at a timing different from that at the time of acquiring the main output signal, such as at the time of acquiring the sub output signal. Further, the calculation cycle of the torque calculation process may be different from the signal cycle.

  In the second embodiment, in the first calculation after the abnormality of the main output signal is detected, the steering torque is calculated based on the main steering torque holding value that is the previous value and the latest sub steering torque. In another embodiment, for example, the main steering torque for a plurality of times is held in the memory as a main steering torque holding value, and is not limited to the previous time. The steering torque may be calculated based on the steering torque. That is, not only the main physical quantity in the calculation immediately before the abnormality of the main output signal is detected, but the main physical quantity in the calculation two or more times before is used as the “main physical quantity before the abnormality is detected” for calculating the target physical quantity. May be. The same applies to the third embodiment.

In the third embodiment, the asymptotic value is calculated by multiplying the absolute value of the difference value between the main steering torque holding value or the steering torque holding value (hereinafter referred to as the previous value) and the sub steering torque by a predetermined coefficient. In accordance with the magnitude relationship between the value and the sub steering torque, it is determined whether the asymptotic value is added to or subtracted from the previous value. In another embodiment, an asymptotic value is calculated by multiplying a value obtained by subtracting the sub steering torque from the previous value by a predetermined coefficient, and the asymptotic value is subtracted from the previous value regardless of the magnitude relationship between the previous value and the sub steering torque. You may make it do. In another embodiment, an asymptotic value is subtracted by multiplying a value obtained by subtracting the previous value from the sub-steering torque by a predetermined coefficient, and the asymptotic value is calculated from the previous value regardless of the magnitude relationship between the previous value and the sub-steering torque. May be added.
The same applies to the calculation using the return asymptotic value of the fifth embodiment.

  In the sixth embodiment, the differential value of the target physical quantity is calculated based on at least one of the differential value of the main physical quantity and the differential value of the sub physical quantity. In another embodiment, the target physical quantity calculated in any one of the first to fifth embodiments may be differentiated as the differential value of the target physical quantity. Similarly, the integrated value of the target physical quantity may be integrated with the target physical quantity calculated in any of the first to fifth embodiments.

(D) Sensor device In the above embodiment, the sensor device is applied to a torque sensor of an electric power steering device. In other embodiments, the sensor device may be applied to a vehicle-mounted device other than the electric power steering device, or may be applied to a device that is not mounted on a vehicle.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

DESCRIPTION OF SYMBOLS 1, 2 ... Sensor apparatus 10 ... Main sensor part 11, 12 ... Main sensor element 15 ... Main output circuit 20 ... Sub sensor part 21, 22 ... Sub sensor element 25 ... Sub Output circuit 40, 50... ECU (control unit)
41 ... Signal acquisition unit 42 ... Abnormality detection unit 43 ... Torque calculation unit (physical quantity calculation unit)

Claims (12)

A main sensor having a main sensor element (11, 12) for detecting a target physical quantity and a main output circuit (15) for generating and outputting a main output signal including a main sensor signal corresponding to a detection value of the main sensor element Part (10);
A sub-sensor element (21, 22) for detecting the target physical quantity, and a sub-output signal including a sub-sensor signal corresponding to a detection value of the sub-sensor element, and generating the main period for a predetermined period shorter than the length of one signal period A sub sensor unit (20) having a sub output circuit (25) for outputting the sub output signal at a timing shifted from the output signal;
A signal acquisition unit (41) for acquiring the main output signal and the sub output signal, an abnormality detection unit (42) for detecting an abnormality of the main output signal and the sub output signal, and the main sensor signal and the sub sensor signal A control unit (40, 50) having a physical quantity calculation unit (43) for calculating a target physical quantity based on at least one of
With
The physical quantity calculator is
When the main output signal is normal, the main physical quantity calculated based on the main sensor signal is the target physical quantity,
The sub-physical quantity calculated based on the sub-sensor signal and the main physical quantity before the abnormality is detected in an undetermined period that is a period from when the abnormality of the main output signal is detected to when the abnormality is confirmed. A sensor device for calculating the target physical quantity based on the above.   2. The sensor device according to claim 1, wherein when the abnormality of the main output signal is determined, the physical quantity calculation unit sets the sub physical quantity as the target physical quantity.   The physical quantity calculation unit is configured to multiply a value obtained by multiplying the main physical quantity before the abnormality of the main output signal is detected by a first transition coefficient greater than 0 and less than 1 and the latest sub physical quantity in the indeterminate period. 3. The sensor device according to claim 1, wherein the target physical quantity is a sum of a value obtained by multiplying 1 by a second transition coefficient obtained by subtracting the first transition coefficient. The physical quantity calculator is
A value obtained by multiplying the main physical quantity before the abnormality is detected by a first transition coefficient greater than 0 and less than 1 in the first calculation after the abnormality of the main output signal is detected in the uncertain period; The target physical quantity is the sum of the latest sub-physical quantity multiplied by a second transition coefficient obtained by subtracting the first transition coefficient from 1;
In the second and subsequent computations of the indeterminate period, the sum of a value obtained by multiplying the target physical quantity of the previous computation by the first transition coefficient and a value obtained by multiplying the latest sub physical quantity by the second transition coefficient The sensor device according to claim 1, wherein the sensor device is a target physical quantity. The physical quantity calculator is
In the first calculation after the main output signal abnormality is detected in the indeterminate period, a value based on a difference value between the main physical quantity before the abnormality is detected and the latest sub physical quantity is first transferred Asymptotic value, the target physical quantity is calculated using the initial transition asymptotic value,
In the calculation after the second time in the uncertain period, a value based on the difference value between the target physical quantity of the previous calculation and the latest sub physical quantity is set as a transition asymptotic value, and the target physical quantity is calculated using the transition asymptotic value. The sensor device according to claim 1 or 2. After the abnormality of the main output signal is detected, when the main output signal becomes normal, in a return waiting period until normal return is determined,
The physical quantity calculation unit calculates a value obtained by multiplying the target physical quantity of the previous calculation by a first return coefficient greater than 0 and less than 1, and a second return coefficient obtained by subtracting the first return coefficient from 1 to the latest main physical quantity. The sensor device according to any one of claims 1 to 5, wherein a sum of a multiplied value is used as the target physical quantity. After the abnormality of the main output signal is detected, when the main output signal becomes normal, in a return waiting period until normal return is determined,
6. The physical quantity calculation unit according to claim 1, wherein a value based on a difference value between the target physical quantity of the previous calculation and the latest main physical quantity is set as a return asymptotic value, and the target physical quantity is calculated using the return asymptotic value. The sensor device according to any one of the above. The control unit (50) includes a differential calculation unit (47) that calculates a differential value of the target physical quantity,
The differential operation unit is
When the main output signal is normal, the differential value of the main physical quantity is the differential value of the target physical quantity,
The sensor device according to any one of claims 1 to 7, wherein a differential value of the target physical quantity is calculated based on the sub physical quantity and the main physical quantity before an abnormality is detected in the undetermined period. The control unit (50) includes an integration calculation unit (48) that calculates an integral value of the target physical quantity,
The integral calculation unit includes:
When the main sensor signal is normal, the integral value of the main physical quantity is the integral value of the target physical quantity,
The sensor device according to any one of claims 1 to 8, wherein an integral value of the target physical quantity is calculated based on the sub physical quantity and the main physical quantity before an abnormality is detected in the undetermined period.   The sensor device according to any one of claims 1 to 9, wherein the main sensor element and the sub sensor element are magnetic detection elements that detect a magnetic flux of a detection target (831) as the target physical quantity.   The sensor device according to claim 10, wherein the main sensor element and the sub sensor element detect a change in magnetic flux that changes according to torque. Sensor device (1, 2) according to claim 11,
A motor (81) for outputting an auxiliary torque for assisting the steering of the steering member (91) by the driver;
A power transmission unit (82) for transmitting the torque of the motor to a drive target (92);
With
The physical quantity calculation unit calculates a steering torque as the target physical quantity,
The said control part is an electric power steering apparatus which has a motor control part (45) which controls the drive of the said motor based on the said steering torque.

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